Since May 2015, agents have been required to publish these fees on their website. About 1 in 4 have not done that and we have reported them to the local councils to investigate. With the rest, we've rounded up their typical fees side by side for your perusal.

Waltham Forest Renters were the first organisation to do this in their area in June. In the north east London borough, rents have risen by a third in the past two years, and the demand seems to have inspired agents to charge the highest average letting fee for a typical two-person household (out of the four boroughs) at £489. Ealing came in cheapest at £374.

Tower Hamlets is home to the most expensive letting agent, the appropriately named Skampi, which charges £900. They also have the cheapest, Tabiner, which charges £40 to a couple.

With competition for homes to rent often very fierce, choosing your letting agent is not always possible. But we hope this information will help renters avoid the worst ones.

The government reckons this transparency will force fees down. If this happens we'll be updating the numbers. And if you see an incorrect number you can report it on the site.

In the meantime, we have volunteers in 13 other local council areas around England working on this project, so will have more areas to report on soon. And if you want to find out about researching your own area, you can register on the website here.

We are indebted to Croydon resident Alex Parsons who created the website and does more of this sort of thing through Inkleby.